The present invention generally relates to sailboards and like water craft which structurally incorporate a downwardly projecting fin for lateral support while in the water.
More particularly, the present invention pertains to detachable fins mounted in supporting channels located in the bottom of said boards and crafts whereby the fins may be removed or adjusted.
Even more specifically, the present invention concerns a parallelogram-shaped nut with biasing spring engaging said channel for locking the fin thereto.